Sweden's foreign minister Carl Bildt has taken the title of best connected world leader on Twitter 2013 – with last year's champion tweeter Herman Van Rompuy slipping out of the top 10 in a list dominated by Europeans.

Bildt has 44 mutual connections with other major political players on the social networking site – meaning he follows them and they follow him back – according to the annual Twiplomacy study produced by the public relations firm Burson-Marsteller.

The next best connected accounts are those run by Catherine Ashton's European Union foreign service, and those of the foreign ministries of Poland, the United Kingdom and France. European Council President Van Rompuy drops from first place last year to 11th, despite increasing his mutual connections with other world leaders from 11 to 19.

Among the top 15 accounts, only one represents a non-European country – that of the Israeli foreign office. The others include British foreign minister William Hague, Finland's Europe minister Alexander Stubb, Norwegian Prime Minister Jens Stoltenberg, and the European Commission. All 45 European governments have a Twitter presence, the study says.

Bildt played down the importance of his global connections on the social networking site, tweeting that his first place "sounds exaggerated". But the study reveals the growing importance of official political activity on Twitter, with almost 78 per cent of United Nations countries having an account of some sort – whether an automated news feed or personal profiles of senior figures.

Although Sweden's Bildt is connected to more of his political peers than any other world leader, his overall 212,000 followers pale into insignificance compared to the 33 million-plus people that track United States President Barack Obama. Yet Obama and the other US government accounts are among the worst connected, mutually following just four world leaders.

After the US president, Pope Francis is the next most followed leader with seven million devotees across several accounts, with the White House's combined English and Spanish-language profiles in third place. Turkey's President Abdullah Gül and Prime Minister Recep Tayyip Erdogan make the top five with 3.4 million followers each. The UK government's account is also in the top 10 most followed.

However, while the number of people followed and following political accounts is growing, the active engagement of world leaders on Twitter still varies. While a third of the 505 accounts analysed are personal profiles of heads of state and government and foreign ministers, only a third do the tweeting themselves and only 14 do so on a regular basis.

Uganda's Prime Minister Amama Mbabazi is the most conversational world leader on Twitter. In Europe, the study highlights Bildt, Stubb, Estonian President Toomas Hendrik Ilves, and Polish Prime Minister Donald Tusk as among the best for producing thought-provoking tweets and replying to followers.

Sweden's foreign minister Carl Bildt has taken the title of best connected world leader on Twitter 2013 – with last year's champion tweeter Herman Van Rompuy slipping out of the top 10 in a list dominated by Europeans